I-RDF, PN148384R7, Page 1
Form I-RDF (12-15)
Obsoletes I-RDF (Version A.4)
Applies to: Indoor or Outdoor, Gas, Direct-Fired
Makeup Air/Heating Systems
Model RDF Series 3
Installation
Model RDF with
Outside Air Hood
!
WARNING:
FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result in serious injury, death, or
property damage.
Be sure to read and understand the installation, operation, and service instructions in
this manual.
Improper installation, adjustment, alteration, service, or maintenance can cause
serious injury, death, or property damage.
— Do not store or use gasoline or other ammable vapors and liquids in the vicinity
of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a phone remote from the building. Follow
the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the re department.
— Installation and service must be performed by a qualied installer, service agency,
or the gas supplier.
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I-RDF, PN148384R7, Page 2
WARNING: On makeup air heaters which also recirculate room air, outside ventilation
air must be provided in accordance with the information shown on the heater
nameplate.
Recirculation of room air may be hazardous in the presence of:
(a) Flammable solids, liquids, and gases;
(b) Explosive materials; or
(c) Substances which may become toxic when exposed to heat.
WARNING: Improper installation, adjustment, alteration, service, or maintenance
can cause property damage, injury or death. Read the installation, operation,
and maintenance instructions thoroughly before installing or servicing this
equipment.
WARNING: Gas-red appliances are not designed for use in hazardous
atmospheres containing ammable vapors or combustible dust, or atmospheres
containing chlorinated or halogenated hydrocarbons. See Hazard Levels
above.
1.0 General
1.1 Hazard Labels and Notices
There are warning labels on the unit and throughout this manual. For your safety, read
the denitions below and comply with all boxes labeled CAUTION, WARNING, and
DANGER during installation, operation, maintenance and service of this heater.
HAZARD INTENSITY LEVELS
1. DANGER: Failure to comply will result in severe personal injury or death
and/or property damage.
2. WARNING: Failure to comply could result in severe personal injury or
death and/or property damage.
3. CAUTION: Failure to comply could result in minor personal injury and/or
property damage.
Hazard Intensity
Levels Apply to
Warnings throughout
this Manual
1.0 General ..............................................2
1.1 Hazard Labels and Notices .......... 2
1.2 General Description .................... 3
1.3 Warranty ....................................... 3
1.4 Installation Codes/Requirements 3
2.0 Location ............................................. 4
3.0 Uncrating/ Preparation .....................4
4.0 Clearances and Dimensions ........... 4
4.1 Clearances ................................... 4
4.2 Dimensions ................................. 5
5.0 Mounting ...........................................5
5.1 Weights ........................................ 6
5.2 Rigging ......................................... 6
5.3 Mounting on Field-Supplied
Supports ...................................... 6
5.4 Mounting on a Roof Curb ............. 6
6.0 Mechanical ........................................9
6.1 Gas Piping and Pressures ........... 9
6.2 Unit Inlet Air ................................. 11
6.3 Supply Air Discharge .................. 15
6.4 Blowers, Drives, and Motors ...... 16
7.0 Electrical Supply and Wiring .........17
8.0 Controls ...........................................19
9.0 Check-Test Start .............................22
Before Startup ................................. 22
Startup ............................................. 23
After Startup ..................................... 25
APPENDIX .............................................26
Technical Data ................................. 26
ADDITIONAL REFERENCES ................26
INDEX ..................................................... 27
INSTALLATION RECORD ....................28
TABLE OF CONTENTS
I-RDF, PN148384R7, Page 3
1.2 General
Description
The information in this manual applies to Model RDF Series 3 direct-red makeup
air heating systems. The typical system consists of a direct-red, natural gas-fueled
burner, and a draw-through blower housed in a weatherized cabinet. The system may
be installed either indoors or outdoors.
This direct-red makeup air system provides tempered makeup air. Makeup air is
dened as air that enters a building or area due to negative pressure created by an air
exhaust load in excess of the volume of entering air. This system warms the outside
air and monitors the volume and temperature of the makeup air added to the building.
The system may be used to provide ventilation in whole building or in spot applications.
In whole building applications, adding controlled makeup air will cause less inltration
of dust and dirt; will eliminate continuous backdraft in chimneys and vents; and will
reduce space heating fuel costs.
This system is available with various air control options to meet a wide range of
application requirements. Depending on the air control option ordered, the supply air
volume may be varied or the outside air may be supplemented with up to 75% building
air (recirculation) for increased energy savings.
These systems are designed-certied to ANSI and CSA Standards. (NOTE: Optional
recirculation is available for U.S. installations only; recirculation is not available for
Canadian installations.)
In order to retain certication, the installer must adhere to the installation and operation
requirements in the instruction manual. These direct-red makeup air systems are not
approved for residential use.
1.3 Warranty
Refer to the limited warranty information on the warranty card included in the "Owner's
Envelope".
1.4 Installation
Codes/
Requirements
Installation should be done by a qualied agency in accordance with the instructions
in this manual and in compliance with all codes and requirements of authorities having
jurisdiction. The qualied agency installing this system is responsible for the installation.
These units must be installed in accordance with local building codes. In the absence
of local codes, the unit must be installed in accordance with the National Fuel Gas
Code ANSI Z223.1a (latest edition) or CAN/CGA B149, Installation Codes for Gas
Burning Appliances. These codes are available from CSA Information Services,
1-800-463-6727.
Before installation, always consult authorities having local jurisdiction to verify that
local codes and procedures are being followed.
The building should always provide adequate relief for the heater to operate at its
rated capacity. It should be noted that this can be accomplished by taking into account,
through standard engineering methods, the structure's designed inltration rate; by
providing properly sized relief openings; by interlocking a powered exhaust system;
or by a combination of these methods. Excessive recirculation or insufcient
ventilation air which results in inadequate dilution of the combustion products
generated by the heater may create hazardous concentrations of carbon dioxide,
carbon monoxide, nitrogen dioxide, and other combustion products into the
heated space.
If the failure or malfunction of this heater creates a hazard to other fuel burning
equipment in the building, interlock the system to open inlet dampers or other such
devices.
Recirculation Requirements - Do not install a system with optional recirculation
(building air) in the presence of ammable solids, liquids, or gases; explosive materials
(i.e., grain dust, coal dust, gun powder, etc.); or substances which may become toxic
when exposed to heat (i.e. refrigerants, aerosols, etc.). If a system with recirculation
is being installed in an area where propane fork trucks or other fossil fuel powered
equipment are used, the ventilation requirements for that equipment must be met.
Recirculation is not recommended in uninsulated buildings where outside temperatures
fall below 32°F (0°C).
If in doubt regarding an application, consult the heater manufacturer's representative
before installation.
I-RDF, PN148384R7, Page 4
Codes for Special Installations: (1) Aircraft Hangar -- Installation in an aircraft
hangar must be in accordance with the Standard for Aircraft Hangars, ANSI/NFPA 409
(latest edition) or CAN/CGA B149 Installation Codes; (2) Public Garage -- Installation
in a public garage must be in accordance with the Standard for Parking Structures,
ANSI/NFPA 88A (latest edition) or the Standard for Repair Garages, ANSI/NFPA 88B
(latest edition) or in Canada with CAN/CGA B149 Installation Codes.
1.0 General
(cont'd)
1.4 Installation Codes/Requirements (cont'd)
2.0 Location
Location must comply with clearances in Paragraph 4.1. Makeup air should enter at
the highest point practical. By doing this, the fresh air will entrain dust laden air at the
ceiling and move it toward the point of exhaust. Also, fresh air directed downward from
the roof or ceiling will mix with hot ceiling air resulting in improved distribution of heat
in the building.
Always introduce fresh makeup air so that it moves across the greatest distance within
the room or building before reaching an exhauster.
3.0 Uncrating/
Preparation
Immediately upon uncrating the unit, check the gas specications and electrical
voltage (system rating plate is in the control compartment) to be sure that they agree
with the supply at the installation site. Check for any damage that may have been
incurred during shipment. If damage is found, document the damage with the carrier
and contact your distributor.
The following control parts are shipped loose inside the unit:
• a 3-position control switch mounted in a 4x4 junction box (except units with Option
AG37) NOTE: If an optional remote console is ordered, this switch is mounted on
the console; the console is shipped separately.
Depending on the gas and/or air controls selected, the following additional parts are
shipped inside the unit or separately.
Gas Controls Shipped-Loose Parts
Options AG30, AG32, AG33,
AG47, AG48
*Remote Temperature Selector
Option AG31 *Remote Temperature Selector, Space Override Thermostat
Option AG36 Remote Console
Air Controls Shipped-Loose Parts
Option AR19, AR22 *Potentiometer
Option AR20, AR23 Remote Pressure Sensor
Option AR32 Toggle Switch
Option AR36 Photohelic Pressure Sensor
Option AR37 Photohelic Pressure Sensor
*If an optional remote console is ordered, these controls are mounted on the console.
The console is shipped separately.
On all sizes with an optional dirty lter switch, the tubing and clamps are shipped
inside the cabinet.
Be sure that all shipped-separate accessories for the installation are available. Other
shipped-separate accessories could include a roof curb, a remote console, an outside
air hood, a disconnect switch, and/or an indoor lter cabinet.
4.0 Clearances
and
Dimensions
4.1 Clearances
Clearances - inches (mm)
Top Control Side
Side Opposite
Controls
Bottom
To Combustibles To Non-Combustibles
3 (76) Width of unit 3 (76) 3 (76) 0 - Curb
Clearance to combustibles is dened as the minimum distance from the heater to a
surface or object that is necessary to ensure that a surface temperature of 90°F above
the surrounding ambient temperature is not exceeded. In order to service the system,
the minimum clearance on the control side of the unit must be equal to the width of the
unit.
I-RDF, PN148384R7, Page 5
4.2 Dimensions
FIGURE 1 - Dimensions (inches and mm)
Dimensions (inches)
Model Sizes A B C D E F G H J K L M
1-20-3, 1-40-3,
1-50-3, 1-65-3
88 37-1/8 44-3/16 84-13/16 45-1/2 24-1/2 10-1/2 5-7/16 14-9/32 15-5/8 21-29/32 19-1/8
2-80-3, 2-120-3 88 48-11/16 68-1/4 84-13/16 69-1/2 52 16-1/4 5-5/16 10-15/16 15-1/2 27-9/32 27-7/32
3-180-3, 3-260-3 135-3/4 61-5/8 82-9/16 132-9/16 83-1/8 64-9/16 19-1/16 5-5/32 13-13/32 21-5/8 37 37-3/32
Model Sizes N P Q R S T U V W X Y Z
1-20-3, 1-40-3,
1-50-3, 1-65-3
7-11/16 14-5/8 12-5/8 31-1/8 31-1/8 21-3/4 18-3/4 7-3/4 5-1/4 13-1/8 8-9/16 42-7/32
2-80-3, 2-120-3 16-5/16 24-21/32 11-7/32 55-3/16 42-5/8 27-1/4 27-1/4 16-5/32 6-11/32 15-3/32 8-3/4 48-15/16
3-180-3, 3-260-3 14-9/16 31-9/16 7-7/16 67-1/8 55-9/16 36-3/4 36-3/4 14-7/16 4 20-7/8 8-11/16 56
Dimensions (mm)
Model Sizes A B C D E F G H J K L M
1-20-3, 1-40-3,
1-50-3, 1-65-3
2235 943 1122 2154 1156 622 267 138 363 397 556 486
2-80-3, 2-120-3 2235 1237 1734 2154 1765 1321 413 135 278 394 691 691
3-180-3, 3-260-3 3448 1565 2097 3367 2111 1640 484 131 341 549 940 942
Model Sizes N P Q R S T U V W X Y Z
1-20-3, 1-40-3,
1-50-3, 1-65-3
195 371 321 791 791 552 476 197 133 333 217 1072
2-80-3, 2-120-3 414 626 285 1402 1083 692 692 410 161 383 222 1243
3-180-3, 3-260-3 370 802 189 1705 1411 933 933 367 102 530 221 1422
* RDF-2 and RDF-3 sys-
tems have double hinged
doors as illustrated. Control
compartment on RDF-1 has
a single hinged door.
** Conguration is for
RDF-2 and RDF-3. The
supply connection on the
RDF-1 systems is above the
control wiring connection.
5.0 Mounting
Mounting the system is the responsibility of the installer. Verify that the supporting
structure has sufcient load-carrying capacity to support the weight.
Depending on the building and its use, determine whether or not additional measures
should be taken to reduce the effect of blower vibration and/or noise.
When selecting a location for an outdoor installation, position the unit so that the air
inlet will NOT be facing into the prevailing wind. A minimum of 14" (356mm) clearance
is required from the bottom of the air inlet hood to the mounting surface.
Prior to installation, be sure that the method of support is in agreement with all local
building codes. For both indoor and outdoor installations, check for service platform
requirements. If an outdoor system is being installed with bottom discharge and/or
return air, a full perimeter roof curb is recommended.
I-RDF, PN148384R7, Page 6
5.3 Mounting on
Field-Supplied
Supports
5.1 Weights
NOTE: Net weights are approximate for the standard system. Optional equipment is
not included.
Net Weight of Basic Model RDF System
Sizes 1-20 1-40 1-50 1-65 2-80 2-120 3-180 3-260
lbs 915 925 935 950 1455 1505 2410 2480
kg 415 420 424 431 670 683 1093 1125
5.2 Rigging
All units are mounted on a full curb cap base furnished with four lifting lugs for attaching
rigging. To prevent damage to the cabinet, use spreader bars with the rigging chains.
FIGURE 2 - Placement of Mounting Rails
A
B
4 x 4 Treated Lumber
FIGURE 3 - Cross
Support Mounting
Requirements
Mounting Rail Placement
Model A (inches) B (inches)
1-20, 1-40, 1-50, 1-65 85-1/4 45-1/2
2-80, 2-120 85-1/4 69-7/16
3-180, 3-260 132-5/8 83-1/16
Model A (mm) B (mm)
1-20, 1-40, 1-50, 1-65 2165 1156
2-80, 2-120 2165 1764
3-180, 3-260 3369 2110
5.4 Mounting on a
Roof Curb
CAUTION: Before installing curb, recheck to be sure that the
correct curb has been ordered. Be sure that the curb selected
matches the unit ordered. Verify the dimensions of the curb
received with the dimension table in FIGURE 4.
Roof Curb
Dimensions for Model
RDF Series 3
Whether the roof curb is Option CJ3 designed for the system or a eld-supplied curb,
the roof curb dimensions in FIGURE 4 and the ductwork opening dimensions in
FIGURE 6 apply.
The roof curb designed for the system includes dividers that will create internal
ductwork and duct connection anges for ease of installation and so that the building
ductwork can be attached before the system is set on the roof curb.
The system is equipped with a load-bearing curb cap which forms an integral part
of the unit. The curb cap provides required clearance from combustibles. Whether
the system is being mounted directly on a surface or being placed "up" on additional
structure, the horizontal length must be supported by two 4x4 treated wooden rails.
Refer to FIGURE 2 for the appropriate lengths and spacing. When the system is placed
on the rails, the curb cap "skirt" must t over the edge of the boards with the rails
setting inside the horizontal length of the curb cap.
If the rails are laid directly on the mounting surface, position them as shown in FIGURE
3. Set the system on the rails leaving the "ends" underneath open for ventilation.
If the wooden rails are not placed directly on a surface, cross-supports should be
placed underneath the rails at the ends and at the cabinet "joint". Refer to FIGURE 3.
IMPORTANT NOTE: Mount an outdoor unit with a minimum of 14" clearance from the
bottom of the inlet air hood to the mounting surface.
5.0 Mounting
(cont'd)
I-RDF, PN148384R7, Page 7
FIGURE 4 - Dimensions of
Optional Roof Curb (Option
CJ3) - Shipped Separately
IMPORTANT NOTE:
Area enclosed by roof curb
must comply with clearance to
combustible materials. If the roof
is constructed of combustible
materials, area within the roof
curb must be ventilated, left open,
or covered with non-combustible
material which has an "R" value of
at least 5. If area within curb is left
open, higher radiated sound levels
may result.
NOTE: Drawing is
not proportional for
all sizes.
Roof Curb Dimensions (± 1/8" or 3mm) and Approximate Weights
Sizes 1-20-3, 1-40-3, 1-50-3, 1-65-3 2-80-3, 2-120-3 3-180-3, 3-260-3
inches mm inches mm inches mm
A 84-5/8 2149 84-5/8 2149 131-3/4 3346
B 43-5/8 1108 67-9/16 1716 82-1/16 2084
C 80-7/8 2054 80-7/8 2054 128 3251
D 39-7/8 1013 63-13/16 1621 78-5/16 1989
Height 16 inches (406 mm)
Weight 171 lbs (78 kg) 224 lbs (102 kg) 307 lbs (139 kg)
Components in Roof Curb Option CJ3
Roof Curb Frame and Internal Ductwork Dividers (See FIGURE 4.)
Item Qty Description
1 2 Curb Front and Back Assemblies
2 2 Curb Side Assemblies
3 4
Full Width Curb Dividers -- two (2) for bottom discharge supply air
duct opening and two (2) for optional return air duct opening
4 2 Cross Dividers for Bottom Discharge Supply Air Opening
5 2 Cross Dividers for Optional Return Air Opening
Roof Curb Corner Hardware
For Top Two
"Holes"
8 5/16" x 1" Lag Screws, P/N 16243
8 5/16" Lockwasher, P/N 1333
For Bottom
Two "Holes"
8 5/16" x 3/4" Hex Head Cap Screw, P/N 16247
8 5/16" Lockwasher, P/N 1333
8 5/16-18 Hex Nut, P/N 1035
Hardware to Assemble and Attach Dividers to make Ductwork Openings
Qty of 64 #10 Sheetmetal Screws, P/N 11813
Components in
Option CJ3 Roof Curb
(Refer to FIGURE 4 to
identify the Item)
Corner
Detail
Curb
1. If installing an Option CJ3 curb, follow these instructions. If installing a eld-supplied
curb, the curb must be level and must be sealed to the system curb cap.
2. Position the roof curb end assemblies and side assemblies as shown in the
drawing in FIGURE 4. Fasten with bolts and lag screws as illustrated in the corner
detail (FIGURE 5).
Roof Curb Installation
Instructions
FIGURE 5 - Option
CJ3 Roof Curb Cross
Section and Corner
Detail
I-RDF, PN148384R7, Page 8
FIGURE 6 - Divider Locations for
Bottom Ductwork Openings
NOTES:
• Drawing is not proportional for all sizes.
• 3/4" (19mm) measurement is the width of the
anges where the roof curb mates with the
heater. Flange surface must be sealed.
• When cutting duct openings in the roof, cut
opening(s) 1” (25mm) larger than duct size
opening for installation clearance.
5.0 Mounting
(cont'd)
5.4 Mounting on a Roof Curb (cont'd)
Roof Curb Duct Opening Dimensions (± 1/8" or 3mm)
Sizes 1-20, 1-40, 1-50, 1-65 2-80, 2-120 3-180, 3-260
inches mm inches mm inches mm
A 23-11/32 593 28-13/32 722 38 965 A
B 20-1/8 511 28-11/32 720 38 965 B
C 5 127 13-15/32 342 11-19/32 294 C
D 10-1/4 260 7 178 4-5/8 17 D
E 25-1/2 648 54-11/16 1389 66-3/4 1695 E
F 11-1/2 292 17-23/32 432 20-1/16 510 F
G 11-15/32 291 8 203 10-15/32 266 G
H 11-1/32 280 11-3/32 282 17-1/4 438 H
3. If the system has a bottom discharge and/or a return air inlet, use the sheetmetal
screws to sub-assemble the dividers. Refer to the dimensions in FIGURE 6 to
appropriately position the roof curb dividers to create the needed duct opening
anges. Attach the dividers to the roof curb with sheetmetal screws. NOTE: If the
system does not have a bottom discharge and/or a return air opening, the dividers
for an opening that is not going to be used may be installed but are not required.
4. Check the assembly for squareness. The curb must be adjusted so that the
diagonal measurements are equal within a tolerance of ± 1/8".
5. Level the roof curb. To ensure a good weatherproof seal between the unit curb
cap and the roof curb, the roof curb must be leveled in both directions with no twist
end to end. Shim as required and secure curb to the roof deck before installing
ashing.
6. Install eld-supplied ashing.
7. Before placing the RDF unit on the curb, apply furnished 1/4" x 1-1/4" foam sealant
tape to the top perimeter surface of the curb, making good butt joints at corners.
The sealant tape must be applied to the curb rails to prevent water leakage into
the curb area due to blown rain and capillary action.
Also place the foam sealant tape on the perimeter of the top surface of the duct
opening(s), being sure to make good butt joints at corners. If installing ductwork
from the top, it is recommended that tape be put on again after the ductwork is
"dropped in", sealing below and above the duct anges.
Roof Curb Installation Instructions (cont'd)
I-RDF, PN148384R7, Page 9
6.1 Gas Piping and Pressures
All piping must be in accordance with the requirements of the National Fuel Gas Code
ANSI/Z223.1 (latest edition) or CSA B149.1 and B149.2. Gas supply piping installation
must conform with good practice and with all local codes. Read this section of the
installation manual to determine the minimum gas supply pressure required to provide
a maximum gas capacity. Minimum gas supply pressure is also stated on the heater
rating plate. The heater manifold terminates at the gas supply connection with a black
iron pipe union. See FIGURE 7. Local codes may require a 6" condensate trap. Gas
connection is either 1", 1-1/4", or 2" depending on the size of the system.
WARNING: High pressure testing of supply lines is acceptable, provided the supply
line has been disconnected from the unit and the pipe end is capped. See Hazard
Levels, page 2.
FIGURE 7 - Gas
Supply Connection
6.0 Mechanical
Capacity of Piping - Cubic Feet per Hour based on 0.3" w.c. Pressure Drop
Specic Gravity for Natural Gas -- 0.6 (Natural Gas -- 1000 BTU/Cubic Ft)
Specic Gravity for Propane Gas -- 1.6 (Propane Gas -- 2550 BTU/Cubic Ft)
Length
of Pipe
Diameter of Pipe
1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4"
Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane
20' 350 214 730 445 1100 671 2100 1281 3300 2013 5900 3599 12000 7320
30' 285 174 590 360 890 543 1650 1007 2700 1647 4700 2867 9700 5917
40' 245 149 500 305 760 464 1450 885 2300 1403 4100 2501 8300 5063
50' 215 131 440 268 670 409 1270 775 2000 1220 3600 2196 7400 4514
60' 195 119 400 244 610 372 1105 674 1850 1129 3250 1983 6800 4148
70' 180 110 370 226 560 342 1050 641 1700 1037 3000 1830 6200 3782
80' 170 104 350 214 530 323 990 604 1600 976 2800 1708 5800 3538
90' 160 98 320 195 490 299 930 567 1500 915 2600 1586 5400 3294
100' 150 92 305 186 460 281 870 531 1400 854 2500 1525 5100 3111
125' 130 79 275 168 410 250 780 476 1250 763 2200 1342 4500 2745
150' 120 73 250 153 380 232 710 433 1130 689 2000 1220 4100 2501
175' 110 67 225 137 350 214 650 397 1050 641 1850 1129 3800 2318
200' 100 61 210 128 320 195 610 372 980 598 1700 1037 3500 2135
Note: When sizing supply lines, consider possibilities of future expansion and increased requirements. Refer to National Fuel Gas Code for additional
information on line sizing.
Gas Supply Piping
Supply Pressure
Requirement by
Manifold Option
These direct-red makeup air systems are designed to operate on a natural gas supply
differential pressure range of a minimum of 4.3-5.0" w.c. plus the manifold pressure
drop. Maximum supply pressure depends on specic unit ring rate and manifold
selection. If the natural gas supply pressure is above the maximum allowed, it is
necessary to install a eld-supplied step-down gas regulator in the supply line. Order
and install the appropriate Gas Regulator Kit, Option CZ1 (1") or CZ2 (1-1/2"). These
kits include spring-loaded, lockup type regulators that comply with national and local
codes specifying that type of regulator. Follow the instructions provided with the kit.
Measure the gas pressure between the step-down regulator and the unit.
WARNING: All components of the gas supply system must be leak tested prior to
placing equipment in service. NEVER TEST FOR LEAKS WITH AN OPEN FLAME.
Maximum Supply Pressure by Manifold
Manifold Option BM75, BM76, BM77 - 1/2 psi
Manifold Option BM78, BM79 - 2 psi
Manifold Option BM80, BM81 - 5 psi
I-RDF, PN148384R7, Page 10
Pilot Supply Pressure
These systems are designed to operate on a natural gas pilot supply pressure of 3.5"
w.c. or propane gas of 6.0" w.c. Measure both operating pressure and pilot supply
pressure with the blower in operation.
Manifold pressure is dened as the gas pressure as measured at the burner pressure
tap. Measure manifold gas pressure with the blowers operating. Minimum gas pressure
at the burner is typically 4.3" w.c. for natural gas or typically 1.5" w.c. for propane gas.
High gas pressure switches included in the gas train monitor gas pressure downstream
FIGURE 8 - Pressure
Tap Locations for
Measuring Manifold
and Pilot Pressure
Manifold Pressure
Gas Pressure
Switches
from the safety valves. If the gas pressure at this point on a system equipped with a
high gas pressure switch (standard with Manifolds BM 78, 79, 80, and 81 or Option
BP2 with other manifolds) exceeds the setpoint, the switch will open the electrical
circuit to the burner, stopping all gas ow. The high gas pressure switch is a manual
reset device.
A low gas pressure switch (Option BP3) will shutoff the gas ow if the gas pressure
drops below the setpoint of the low pressure switch. The low gas pressure switch will
automatically reset when the gas pressure rises above the setpoint.
(NOTE: Model RDF units manufactured prior to April 1993 installed indoors with
optional gas pressure switches require a 3/4" vent line to the outdoors. Beginning with
units manufactured April 1993, the gas pressure switches incorporate a vent limiting
device and do not require venting to the outdoors.)
6.0 Mechanical
(cont'd)
Minimum Supply Gas Pressure ("w.c.) for Full Fire
Manifold Option BM75 BM76 BM77 BM78 BM79 BM80 BM81
with Gas Control
Option
AG1 AG3 AG 30, 31, 32, 33, 36, 37, 47, 48, or 51
Manifold Size 1" 1" 1" 1" 1" 1-1/4" 1-1/4" 2"
MBH Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro
250 4.0 1.4 4.0 N/A 4.1 1.6 4.3 1.5 4.4 1.6 4.6 1.6 4.5 1.6 5.1 1.8
500 5.3 1.9 5.0 N/A 5.8 2.3 6.2 2.2 6.0 2.3 5.2 1.9 5.0 1.7 5.3 1.9
750 7.5 2.7 6.8 N/A 8.5 3.3 9.5 3.3 8.4 3.3 6.1 2.3 5.7 2.0 5.5 1.9
1000 12.4 4.7 11.7 4.6 7.4 2.8 6.7 2.4 5.8 2.1
1250 9.1 3.5 8.0 2.9 6.2 2.2
1500 11.2 4.3 9.6 3.5 6.6 2.4
1750 13.6 5.3 11.5 4.2 7.2 2.6
2000 16.5 6.3 13.7 5.0 7.8 2.8
2500 23.3 8.9 18.9 7.0 9.4 3.4
3000 11.3 4.1
6.1 Gas Piping and Pressures (cont'd)
Supply Pressure Requirement by Manifold Option (cont'd)
I-RDF, PN148384R7, Page 11
6.2.1 Outside Air Hood or Indoor Filter Cabinet
6.2 Unit Inlet Air
Option AS2, Outside Air Hood
Option AS6, Outside Air Hood with 1" Filters
Option AS7, Outside Air Hood with 2" Filters
Option AW3, Indoor Filter
Cabinet with 1" Filters
Option AW6, Indoor Filter
Cabinet with 2" Filters
FIGURE 9 - Dimensions
and Weights
Dimensions
Size 1-20, 1-40, 1-50, 1-65 2-80, 2-120 3-180, 3-260
inches mm inches mm inches mm
A 38 965 62 1575 74-1/4 1886
B 55 1397 54 1372 64 1626
C 36 914 47-1/2 1207 61-3/8 1559
D 35-9/16 903 59-9/16 1513 71-9/16 1818
E 33-1/8 841 44-5/8 1133 58-1/2 1486
F 19-1/2 495 19-1/2 495 19-1/2 495
G (Duct Connection) 32-15/16 837 56-15/16 1446 69-3/8 1762
H (Duct Connection) 30-3/8 772 41-7/8 1064 57-7/16 1459
Weights and Filter Sizes
Model Sizes
Fltr
Qty
AS6, AW3 AS7, AW6 AS2 AS6 AS7 AW3 AW6
Filter Size lbs kg lbs kg lbs kg lbs kg lbs kg
1-20, 1-40, 1-50, 1-65 3 12x35x1 12x35x2 225 102 250 113 270 122 100 45 120 54
2-80, 2-120
4 12x35x1 12x35x2
310 141 350 159 380 172 150 68 180 82
4 12x24x1 12x24x2
3-180, 3-260 12 12x35x1 12x35x2 400 181 450 204 490 222 200 91 240 109
Installation Instructions for Optional Screened Air Hood for Outdoor Units (Options AS2,
AS6, AS7) and Filter Sections for Indoor Units (Options AW3, AW6)
All of these air inlet accessories are designed to be attached directly to the system
cabinet. To prevent damage, it is recommended that the system be set in its permanent
location before installing the air hood or lter cabinet option. All are shipped separately;
installation requirements depend on the size (see below).
Provide a minimum of 14" (356mm) clearance from the bottom of the air hood to the
mounting surface.
Hood and Filter Cabinet Options by ITEM and Application
Item Options Description For Sizes Installation Requirements
1
AS2, AS6,
AS7
Outdoor Screened Air Hood
with & without lters
1-20, 1-40, 1-50,
1-65, 2-80, 2-120
Factory Assembled; Field Installed -
Follow instructions below.
2
AS2, AS6,
AS7
Outdoor Screened Air Hood
with & without lters
3-180, 3-260
Field Assembled and Installed - Follow
instructions pages 12 to 15.
3 AW3, AW6
Indoor Filter Cabinet with
Filters
All
Factory Assembled; Field Installed -
Follow instructions below.
CAUTION: It is
recommended
that the inlet to the
outside air hood
NOT be facing into
prevailing wind.
Installation STEPS for
ITEMS 1 and 3 in the
Table above - Refer to
FIGURE 10.
1) Remove the sheetmetal screws from the bottom rear inset and across the top rear
of the cabinet.
2) Align edges of assembly to the slip grooves. Slide top edge of assembly under the
lip formed by the top rear of the cabinet.
3) Rotate the inlet assembly so that it ts into the recess across the bottom of the
cabinet. Replace all screws removed in Step 1.
4) If the system has lters with an optional dirty lter light, follow the instructions
beginning on page 18 to attach the sensing tubes.
I-RDF, PN148384R7, Page 12
6.0 Mechanical
(cont'd)
Outside
Air Hood
or Filter
Cabinet
Assembly and
Installation
Instructions for
ITEM 2 in the Table
on page 11 - Refer to
FIGURES 11A-11N.
Option AS2, Outdoor
Screened Air Hood without
Filters - Pkg P/N 71150
Option AS6, Outdoor
Screened Air Hood with 1"
Filters - Pkg P/N 71152
Option AS7, Outdoor
Screened Air Hood with 2"
Filters - Pkg P/N 72627
FIGURE 10 - Attach
factory assembled
Cabinet or Hood
Option Components (qty in parenthesis) AS2 AS6 AS7
Top of Inlet Hood Cabinet Section (1) 91575
Top of Inlet Hood (1) 91576
Clamp for Top Seam (Hood to Cabinet) (1) 91577
Bottom of Hood Cabinet Section (1) 91567
Supports (2 pieces per leg) (6) 91581
Left Side of Hood (1) 91568
Right Side of Hood (1) 91569
Intermediate Posts - Cabinet Section (2) 91578
Rt/Lft Corner Post - Cabinet Section (2) 91579
Doors (Filter Access on AS6 and AS7) (2) 91585
Center Louver Top/Bottom Supports (2) 91582
Factory-assembled Louver Sections w/Screen (2) 113003
Top and Bottom Filter Channels N/A (2) 91580 (2) 94224
Pre-assembled Center Filter Channels N/A (5) 91586 (5) 94223
Top/Btm Filter Block Off Plate N/A (2) 91584 (2) 98764
Filter Block Off Sections N/A (6) 263784 (5) 263784
Permanent Filters N/A (12) 1", 87251 (10) 2", 94383
Sheetmetal Screws #10 x 1/2" long (100) 11813
Screws 1/4-20 x 5/8" long (bolt type) (15) 10393
Hex Nuts 1/4-20 (Keps) (15) 7328
Sheetmetal Screws #14-110 x 3/4" long (3) 41463
J Type Clip-On Nut (5) 1849
1. Screened Air Inlet Hoods with Filters (Options AS6 and AS7 for Sizes 3-180, 3-260) - Build lter racks and
cabinet section; follow all Steps.
Screened Air Inlet Hood without Filters (Option AS2 for Sizes 3-180, 3-260) - Build cabinet section; skip Steps
1A, 1B, and 1C. Start with Step 1D ignoring lter rack illustrations.
Step 1A - Assemble Inner Side of Filter Rack
(Applies to Options AS6 and AS7 only; for Option AS2
without lters, proceed to Step 1D)
Parts Required -- Right corner post, left corner post, three of the
ve pre-assembled center lter channels, and twelve 1/2" long
screws
Corner posts come with two sets of holes.
For 1" lters (Option AS6), attach the three lter channel
assemblies using the holes in the corner posts closest to the
inside.
For 2" lters (Option AS7), attach the three lter channel
assemblies using the holes in the corner posts closest to the
outside edge.
6.2.1 Outside Air Hood or Indoor Filter Cabinet (cont'd)
6.2 Unit Inlet Air (cont'd)
FIGURE 11A
I-RDF, PN148384R7, Page 13
Step 1 B - Sub-assemble Top and Bottom Filter Channels and
Filter Blockoff Plates (AS6 & AS7)
Parts Required - Top and bottom lter channel; top and bottom lter blockoff
plates; and 14 screws (1/2" long)
Assemble the top blockoff plate and the top lter channel being sure the lter
channel groove is on the same side as the 90° bend in the blockoff plate but
directed away from it. Use seven screws to attach the top blockoff plate to the
top lter channel. Repeat the process with the bottom lter channel and bottom
blockoff plate.
Step 1C - Assemble Outer Side of Filter Rack
(Options AS6 and AS7 only)
Parts Required - Two intermediate posts; two remaining
pre-assembled center lter channels; the top and bottom
lter channel/blockoff plate assemblies form Step 1B; and 12
sheetmetal screws (1/2" long)
For 1" lters (Option AS6), attach the channel assemblies to the
holes closest to the inside of the intermediate posts.
For 2" lters (Option AS7), attach the channel assemblies to the
holes closest to the outside edge of the posts.
P/N 91575 Top of Inlet
Hood Cabinet Section
Intermediate
Post
Corner
Post
Intermediate
Post
Corner
Post
Step 1D - Attach Cabinet Section To Corner Posts and
Intermediate Posts (Options AS2, AS6, AS7)
Parts Required - Cabinet top; the two corner cabinet posts (if inlet hood
with lters, posts will be sub-assembled to lter channels - Step 1A) (if
AS2 with no lters, ignore illustrated lter rack); the two intermediate
cabinet posts (if inlet hood with lters, posts will be sub-assembled to lter
channels - Step 1C); and six 1/2" long sheetmetal screws.
Attach cabinet section top to the four posts as illustrated.
Step 1E - Attach Cabinet
Section Bottom
Parts Required - Subassembly
from Step 1D; cabinet section
bottom; and six 1/2" sheetmetal
screws.
Position the cabinet section
bottom to the inside of the
four posts (corners). Attach as
illustrated.
2. Assemble and Install Support Legs
Step 2A - Sub-assemble Legs
Step 2B - Install
Support Legs
Parts Required - Three
sub-assembled legs and
three 3/4" sheetmetal
screws
Attach leg assemblies to
cabinet bottom.
Parts Required - Six support
leg halves and six 5/8" bolts
and nuts
Assemble support legs as
illustrated. Adjust legs to
shortest length and tighten
bolts nger tight. Length of
supports will be re-adjusted
to suit the application after
cabinet is installed.
FIGURE 11B
FIGURE 11C
FIGURE 11D
FIGURE 11E
FIGURE 11F
FIGURE 11G
I-RDF, PN148384R7, Page 14
4. Assemble Air Inlet Hood Section
Step 4A - Attach Hood Sides
Attach the sides to
the intermediate
posts and bottom
panel of the
installed cabinet
section.
Step 4B - Attach Hood Section Top
Parts Required - Hood
section top and ten
1/2" long screws
Attach hood
section top as
illustrated.
Parts Required - Right
and left triangular
shaped sides and 18
sheetmetal screws
(1/2" long)
6.2.1 Outside Air Hood or Indoor Filter Cabinet (cont'd)
6.0 Mechanical
(cont'd)
6.2 Unit Inlet Air
(cont'd)
Assembly and Installation Instructions for ITEM 2 in the Table on
page 11 (cont'd)
RDF
Top
Cabinet Section
of Inlet Hood
Remove screws and
slide edge of cabinet
underneath top.
3. Attach Assembled Cabinet Section
Step 3 - Attach Filter Cabinet to System
On the air inlet opening side of the system cabinet, remove the sheetmetal
screws from the bottom rear inset and the screws across the top edge.
Align the edges of the inlet hood cabinet section with the grooves in
the system cabinet. Slide top edge of the inlet hood cabinet section
underneath the edge of the system cabinet top.
Rotate the assembly so that it ts into the recess across the bottom of
the cabinet opening. Attach by replacing the two corner screws and one
center screw across the top, the three screws across the bottom, and one
halfway up on each side as illustrated.
Adjust the support legs to the appropriate height and tighten bolts
securely.
Step 4D - Install Center Louver Supports
Step 4E - Install Louvers
Parts Required - Two factory-assembled louver sections;
19 screws (1/2" long); and ve Tinnerman clips
Install factory
assembled
louver sections.
AS6 & AS7 - Slide filters and
blockoff sections into filter
racks. Install side panels which
are also the filter access doors.
Step 4C - Install Top Clamp
Parts Required - Top clamp and nine 5/8"
long screws (bolt type) and nuts
Parts Required - Center louver
supports and four 1/2" long screws
Fit clamp over
seam and
attach as
shown with bolt-
type screws and
nuts.
At the holes in the
center of the top and
bottom of the hood, use
the screws to attach the
center louver supports
inside the hood.
FIGURE 11H
FIGURE 11J FIGURE 11K
FIGURE 11L FIGURE 11M
FIGURE 11N
Position one louver section in the left
side of the hood; attach it to the hood
side and the center supports. Install
the other louver section in the right
side. In the center, join the two louver
sections with ve screws and clips.
I-RDF, PN148384R7, Page 15
Step 5. - Install Filters, Block Off Sections and Door Panels
On hoods with lters, position lters and blockoffs on lter racks.
If the systems has an optional dirty lter switch, follow the instructions on page 19 to connect the sensing tubes.
Slide the "door" panels into position on each side of the cabinet section. Fasten each panel with two 1/2" long screws.
Distribution of Makeup Air
Makeup air can be introduced to the building either through distribution ducts or through
controlled pressurization with little or no ductwork. Makeup air should be introduced
and maintained using the lowest possible air velocity. With ductwork distribution, this
is accomplished using a multiplicity of discharge openings over the greatest centerline
distance. When a makeup air system is automatically controlled to maintain a set
building pressure, the entering air will travel naturally toward the relief areas at the
perimeter walls using the building structure as the distribution ductwork.
Makeup air should enter at the highest point practical. By doing this, the fresh air will
entrain dust laden air at the ceiling and move it toward the point of exhaust. Also, fresh
air directed downward from the roof or ceiling will mix with hot ceiling air resulting in
improved distribution of heat in the building.
Always introduce fresh makeup air so that it moves across the greatest distance within
the room or building before reaching an exhauster.
Proper sizing of warm air ductwork is necessary to ensure a satisfactory heating
installation. The recognized authority for such information is the Air Conditioning
Contractors Association, 1228 17th Street, N.W., Washington, DC 20036. A manual
covering duct sizing in detail may be purchased directly from them.
The type of duct installation depends in part on the type of construction of the
roof (wood joist, steelbar joist, steel truss, pre-cast concrete, etc.) and the ceiling
(hung, ush, etc.).
Rectangular ducts should be constructed of not lighter than No. 26 U.S. gauge
galvanized iron or No. 24 B&S gauge aluminum.
All duct sections 24" or wider, and over 48" in length, should be cross-broken on
top and bottom and have seams or angle-iron braces. Joints should be S and drive
strip or locked.
Warm air ducts should not contact masonry walls. Insulate around all air ducts
through masonry walls with not less than 1/2" of insulation.
Insulate all exposed warm air ducts passing through an unheated space with at
least 1/2" thickness of insulation.
Duct Supports - Suspend all ducts securely from adjacent building members. Do
not support ducts from unit duct connections.
Duct Connections - At the heater, use a exible canvas connection on indoor
units to eliminate vibration transmission.
On outdoor roof curb, down discharge connections, either drop an appropriate
sized and anged duct into the roof curb prior to setting the unit or attach ductwork
to the bottom ange (using curb dividers as ductwork). If dropping ductwork from
the top, it is recommended that the top perimeter be sealed above and below
the added ductwork. Do not use screws. See ductwork connection locations and
sizing, pages 7 and 8.
On outdoor horizontal installations, the ducts can be slid over the ange of the
heater and then sealed for an airtight and watertight t. On horizontal duct-to-heater
connections and connections to the anges at the bottom of the curb, use sheetmetal
screws to fasten ducts to the heater ange.
Use stiffening anges around the perimeter of all duct connections.
Return Air Duct - The return air duct must be sized for a pressure drop of .5"
w.c. at 2440 fpm in order to balance the system. If not sized properly, there may
be difculty in obtaining the desired airow over the burner when the return air
damper is full open.
6.2.2 Evaporative
Cooling Module
If installing an evaporative cooling module, it is shipped separately. Follow the
instructions in the manual with the evaporative cooling module.
6.3 Supply Air
Discharge
Sizing and Installation
of Distribution
Ductwork
(See FIGURE 1, page 4, for
duct opening dimensions.)
I-RDF, PN148384R7, Page 16
6.0 Mechanical
(cont'd)
6.4 Blowers, Drives, and Motors
Belt Tension - Check belt tension. Proper belt tension is important to the long life
of the belt and motor. A loose belt will cause wear and slippage. Too much tension
will cause excessive motor and blower bearing wear. If adjustment is required, adjust
belt tension by means of the adjusting screw on the motor base until the belt can be
depressed 1/2" to 3/4" (FIGURE 12). Tighten the lock nut on the adjusting screw. Be
sure the belt is aligned in the pulleys.
FIGURE 12 - Belt
Tension
Motor and Belt Shipping Position for Sizes 2-80, 2-120, 3-180, 3-260 - To relieve
tension on the motor mounting bracket, the belt(s) are taken off the motor and blower
sheaves before shipping. The belt(s) are taped to the blower shaft to prevent loss or
damage during shipment. Install the belt(s) and adjust for proper belt tension.
Blower Pulley - Size 2-80 and 2-120 systems equipped with 3 and 5 HP motors with
a 15.4" diameter and larger blower pulley or a 7-1/2 HP and larger motor and all Size
3-180 and 3-260 systems are equipped with a split taper bushing in the blower pulley.
The split taper bushings must be loosened in order to remove the pulley. Follow these
instructions to loosen the bushing.
1) Notice that there are three cap screws in the bushing and two holes without
screws, called push-off holes (See FIGURE 13).
2) Remove the three cap screws.
3) Put two of the cap screws into the two push-off holes. Tighten these two screws
evenly until the pulley is loosened.
4) Pulley may now be removed from the shaft.
Blower Speed Adjustment - Units are set at the factory for the RPM required to
meet the CFM and external static pressure specied on the order. If the estimated
external static is incorrect, or changes are made to the duct system, the blower
RPM may have to be changed. Motors are equipped with adjustable pitch pulleys
which permit adjustment of blower speed. Instructions are included in Paragraph 9.0,
Check-Test-Start for adjusting blower speed.
Blower Rotation - Each blower housing is marked for proper rotation. Instructions for
checking blower rotation are included in the startup procedures in Paragraph 9.0.
Motor Loads - Use an ammeter to check motor amps. Amps may be adjusted
downward by reducing blower RPM or by increasing duct system static pressure. For
accurate amps, read the motor manufacturer's rating plate; amps will vary depending
upon motor manufacturer. The chart below can be used for sizing line wiring.
3 Cap
Screws
FIGURE 13 - Split
Taper Bushing
2 Push-Off Holes
CAUTION: The motor amp chart lists full load amp requirement
of standard motor and standard controls. Optional controls
will increase amp requirement. Add motor amps and control
amps for approximate unit full load amps. System FLA is
shown on the rating plate.
Blower Motor Full Load Amps (open motors)
Motor HP 115V/1 230V/1 208V/3 230V/3 460V/3 575V/3
1/2 9.8 4.9 2.2 2.0 1.0 N/A
3/4 13.8 6.9 3.1 2.8 1.4 N/A
1 16.0 8.0 4.1 3.6 1.8 1.4
1.5 N/A 10.0 5.75 5.2 2.6 2.0
2 N/A N/A 7.5 6.8 3.4 2.4
3 N/A N/A 10.6 9.6 4.8 3.6
5 N/A N/A 16.8 15.2 7.6 5.4
7.5 N/A N/A 21.0 19.0 9.5 8.4
10 N/A N/A 29.0 25.2 12.6 10.4
15 N/A N/A 42.0 40.0 20.0 16.0
20 N/A N/A 53.0 50.0 25.0 20.0
25 N/A N/A 66.0 63.0 31.5 26.0
30 N/A N/A 78.0 74.0 37.0 28.5
I-RDF, PN148384R7, Page 17
7.0 Electrical
Supply and
Wiring
All electrical wiring and connections including electrical grounding MUST be completed
in accordance with local, state and national codes and regulations and with the
National Electric Code (ANSI/NFPA 70) or in Canada the Canadian Electrical Code
Part 1 C.S.A. C.22.1.
Run a separate line voltage supply directly from the building electrical panel to the
disconnect switch for the system. All external wiring must be within approved conduit
and have a minimum temperature rise rating of 60°C. For motor load amps, see
Paragraph 6.4 or check the motor nameplate. System FLA is on the rating plate.
Specic wiring diagrams and complete instructions are packed with each unit and
should be kept readily accessible in legible condition.
Wire Gauge - 100 ft (30M) maximum
Full Load Amps 5 10 15 20 25 30 35 40
Wire Gauge 14 14 12 10 8 8 6 6
Convenience Outlet
Option
CAUTION: If any of the original wire in the unit must be replaced, the replacement
wire must have a temperature rating of at least 105°C except for controls mounted in
the discharge airstream which must be 150°C. See Hazard Levels, page 2.
When a convenience outlet option is included, an individual power supply must be
provided to the receptacle. This circuit MUST BE on a ground fault breaker to meet
requirements. All wiring to the convenience outlet must meet National Electrical Code
ANSI/NFPA No. 70 (latest edition) or the Canadian Electrical Code Part 1-C.S.A.
Standard C22.1. and any local or utility codes that may apply.
Disconnect Switch
A safety disconnect is required. Refer to FIGURE 14 for recommended location and
install the disconnect switch in accordance with Article 430 of the National Electrical
Code ANSI/NFPA 70 or in accordance with Canadian Electrical Code Part 1-C.S.A.
Standard C22.1. When attaching the disconnect switch to the heater, use hardware
with "teeth" to provide electrical grounding. The "teeth" should face the disconnect
switch, scratching off the painted surface. Attach the disconnect tightly against the
heater cabinet. Run cable so that it does not interfere with cabinet panels or doors.
When providing or replacing fuses in a fusible disconnect switch, use dual element
time delay fuses and size according to 1.25 times the maximum total input amps.
Control Wiring
A 7/8" diameter opening suitable for watertight conduit connection is provided as the
entrance of 24-volt control wiring to the electrical compartment. For location, see
FIGURE 14, page 18. Low voltage wiring must be in individual conduit, separated from
primary high voltage wiring.
Volts Wire Gauge Total Wire Length Distance from Unit to Control
Control Wiring Maximum Lengths (ft)
24 18 150 75
24 16 250 125
24 14 350 175
Control Wiring Maximum Lengths (M)
24 18 45.7 22.9
24 16 76.2 38.1
24 14 106.7 53.3
CAUTION: Supply voltage and 24-volt control wiring cannot be installed in the same
conduit. Maxitrol systems will be adversely affected if control wiring is in conduit
with supply voltage wiring. If required, eld-supplied wiring between any Maxitrol
components must be completed with shielded wiring.
A 3-position control switch mounted in a 4x4 box is supplied with each system (excep-
tion - not included with systems with Option AG37 designed for computer control),
either packed loose inside the unit, or if an optional control console (Option RC13 or
RC14; See FIGURE 15) is ordered, the switch is mounted on the console.
Control wiring requirements depend on the options selected. Follow the custom wiring
diagram supplied with the system to connect any remote controls. In this paragraph,
I-RDF, PN148384R7, Page 18
FIGURE 14 - Location of Gas
Connection, Electrical Supply
Connection, and Control Wiring
Connections on RDF Series 3
Direct-Fired Systems
NOTES:
* RDF-2 and RDF-3 Series 3 systems have double hinged
doors as illustrated. Control compartment on RDF-1 Series 3
systems has a single hinged door.
** Conguration shown is for RDF-2 and RDF-3 Series 3. The
supply connection on the RDF-1 Series 3 systems is above
the control wiring connection.
Disconnect
Switch
Location
FIGURE 15 - Remote
Console Dimensions
Locations of Knockout
Holes (dimensions to
centerlines)
Technical Data of the Remote Console (Variations depend on options selected; consult custom wiring diagram
for controls and to determine wiring required.)
Control
Switch
Qty of
Lights*
Temperature
Selector**
Potentiometer
***
Dimensions - inches (mm)
L**** H**** D
Yes 3 Yes No 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 3 No No 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 3 Yes Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 3 No Yes 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 4 Yes No 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 No Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 Yes Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 No No 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
* 3 - Blower On, Burner On, and Safety Lockout on both RC13 and RC14; 4th light is
Dirty Filter Indicator on Option RC14 only
** On the console with Gas Control Options AG 31, 32, 33, 47, or 48
*** On the console with Air Control Options AR19 or AR22
**** Subtract 1" (25mm) when recessing
Dirty Filter Light FIGURE 16 - Option
RC14 with Dirty
Filter Light and
Potentiometer
7.0 Electrical
Supply and
Wiring (cont'd)
Control Wiring (cont'd)
there is a brief description of the optional electrical controls used for airow. Refer to
the operation manual, Form O-ADF/RDF, for additional control information.
Remote Console
If ordered, the optional remote console is shipped separately. Remote consoles include
terminal blocks for wiring. Depending on what gas control or inlet air options were
ordered, the console could include a temperature selector and/or a potentiometer. If
a dirty lter switch is ordered the indicator light is on the console. See FIGURE 15 for
console size.
When a console with a dirty lter indicator is selected, the remote console includes
a fourth light (dirty lter indicator light). The light is activated by an adjustable,
single-pole/normally open differential pressure switch that senses air pressure across
the lter bank. There are eld-installation procedures that must be done for the proper
operation of the dirty lter indicator light.
Dirty Filter Light Installation Instructions
Before the system is operating, connect the sensing tubes from the switch
to their sensing locations in the eld-installed lter cabinet. (Cabinet installation
instructions are in Paragraph 6.2.)
1) Run the tubes through the holes in the cabinet wall. Pull gently to extend the
tubing to its entire length without stress.
2) Position the tubing approximately at the center of the height of the lter rack.
3) Identify the tube connected to the positive connection on the switch (FIGURE
17) as the positive pressure tube. Determine the length of tubing required to
attach the positive pressure tube so that it will sense pressure at the inlet
side of the lter rack.
Identify the tube connected to the negative connection on the switch (FIGURE
17) as the negative pressure tube. Determine the length of tubing required to
I-RDF, PN148384R7, Page 19
FIGURE 17 - Dirty
Filter Pressure Switch
Set screw
(on front of
switch) must
be manually
adjusted after
system is in
operation.
Negative pressure connection
is toward the "front or top" of
the switch (senses blower side
of lters)
Positive pressure connection is
toward the "back or rear" of the
switch (senses air inlet side of lters)
FIGURE 18 -
Discharge Sensor
and Mixing Tube
attach the negative pressure tube so that it will sense the pressure at the
blower side of the lter rack.
(NOTE: Tubing shipped is the same length for all sizes of systems; cut to the
appropriate length for the smaller systems.)
4) If required, cut the tubing to the proper lengths. Using the clamps provided,
attach the ends of the tubing to the lter rack at about center height being careful
not to kink or compress the tubing.
After the system is operating, the lter switch must be manually set. With
clean lters in place, blower doors closed, and blower in operation, increase the
pressure setting by adjusting the set screw on the switch clockwise until the lter
light is energized or the screw is bottomed out. At that point, adjust the set screw
three full turns counterclockwise or until the screw is top ended. At that setpoint,
the lter light will be activated at approximately 50% lter blockage.
8.0 Controls
Discharge Sensor (Maxitrol) for Gas Control Options AG30, AG31,
AG32, AG33, AG47, AG48 - A discharge sensor may be shipped separately for
eld installation. Attach the discharge sensor and mixing tube in the ductwork about six
feet (1.8 M) from the discharge opening of the system.
The sensor housing is not waterproof. If the installation is outdoors, eld-fabricate a
waterproof protective enclosure for the discharge sensor, being careful not to affect its
air temperature sensing capability. If the ductwork is insulated, be sure that the sensing
bulb is mounted so that it is fully exposed to the airstream being sensed.
Refer to the wiring diagram and connect the sensor to the terminal strip in the blower
section electrical box. Use shielded wire to alleviate any electrical interference that
may cause an erroneous discharge temperature reading.
Outside Air Cutoff Control (Option BN2) - After sensing pilot ame, the
burner ignites at its lowest input rate. The "amount of heat" required to reach the
desired discharge temperature also depends on the temperature of the incoming
outside air. The outside air cutoff (high ambient control) is factory set at 60°F
(adjustable 25-250°F). The burner reacts differently depending on the entering air
temperature and the setting on this control. The burner --
• may not ignite (pilot valve will not open);
If the actual temperature of the outside air is above the setpoint on the outside air
control, the burner will not ignite.
• may modulate to satisfy discharge setting;
• would shutdown completely only on Option BN2 control, once burner has been
red; or
Modulating operation will depend on the temperature rise between the outside air
and the discharge air setting.
• may remain on continuous low re.
If the outside air control is set too high, the burner will continuously burn on low re
as long as the control switch is set to "winter".
When the outside air control is set properly for the climate, the system blower will
continue to provide the required makeup air (ventilation) at the ambient outdoor
temperature (burner not operating) even when the control switch is set to "winter".
If at startup, it is determined that the outside air cutoff control is not set properly,
change the setting on the control (located in the main electrical compartment) and test
for proper operation.
FIGURE 19 - Control
used for Outside Air
Cutoff and
Discharge
Temperature Low
Limit (Freezestat)
I-RDF, PN148384R7, Page 20
FIGURE 20 -
Optional
Door Switch
FIGURE 22 -
Optional
Potentiometer
FIGURE 23 -
Pressure Null
Switch
FIGURE 21 -
Optional
Firestat
8.0 Controls
(cont'd)
Discharge Temperature Low Limit (Option BE2) - If the system has an
optional low limit switch for discharge temperature (freezestat), the control is in the
blower section electrical box. The sensing bulb must be eld-mounted in the blower
discharge duct connector. Uncoil the control and extend the bulb to the blower
discharge, being careful to not interfere with any mechanical parts. Use the bulb holder
provided and mount the sensor according to the manufacturer's instructions.
Door Switch (Option BX1) - If the system is to be used as an overhead door
heater, an optional door switch (Option BX1) must be installed. The function of the
switch is to energize and interlock the system when an outside overhead door reaches
approximately 80% of full open travel. The switch will de-energize the system when
the overhead door closes approximately 20%. Follow the installation instructions in the
door switch option package and the wiring diagram.
Firestat (Option BD2) - If the system has an optional restat, the control is factory
installed in the heated airstream so that the sensor can be extended into the duct. The
restat requires manual reset and is installed in an accessible location.
Optional Potentiometer (applies to systems with Air Control Option
AR19 for makeup air only or AR22 for outside and recirculation air)
- If the system includes Air Control Option AR19, the discharge damper is controlled
by a manually set potentiometer. If the system includes Air Control Option AR22, the
potentiometer controls the return air damper. The potentiometer is shipped loose in the
control compartment, or if a remote console is ordered, it is mounted on the console.
Follow the wiring diagram to connect the potentiometer.
Optional Pressure Null Switch (applies to systems with Air
Control Option AR20 for makeup air only or AR23 for outside and
recirculation air) - If the system includes Air Control Option AR20, the discharge
damper is controlled by a pressure null switch. If the system includes Air Control
Option AR23, the pressure null switch controls the return air damper. The pressure null
switch is shipped in the control cabinet. Refer to the following paragraphs and to the
manufacturer's installation instructions to install and connect this switch.
The pressure null switch is Dwyer #1460-0 with a range of .01-.12" w.c. The pressure
null switch is a diaphragm operated differential pressure switch used in makeup air
applications to control building pressure. It maintains a selected positive or negative
pressure setpoint by changing the amount of outside air being introduced to the
building through the modulating outside air dampers. As more pressure is required in
the building, the pressure null switch activates the damper motor driving the outside
air damper towards the full open position and the recirculated air damper towards
the closed position. Conversely, as less pressure is required, the switch drives the
dampers in the opposite direction.
Installation
Instructions for
Pressure Null Switch
(See FIGURE 24):
Select an indoor location free from excessive vibration where oil or water will not drip
on the switch and where ambient temperature will be within a range of -30°F (dry air)
to 110°F.
Mount the switch with the diaphragm in a vertical plane. The switch is position sensitive
and is calibrated to operate properly when the diaphragm is vertical. Mount switch
securely.
Connect the pressure taps on the top of the switch to sources of air pressure differential.
Metal tubing with 1/4" O.D. is recommended but any tubing which will not unduly
restrict the airow can be used. To maintain a positive building pressure, vent the
low pressure tap to the outdoors and allow the high pressure tap to monitor building
pressure. To maintain a negative building pressure, reverse the functions of the high
and low pressure taps. In either case, be sure that the outdoor vent is protected from
the wind and screened from insects.
Adjustment of the Switch - The "high" actuation point of the null switch is indicated on
a calibrated scale secured to the transparent range screw enclosure. Building pressure
is set by turning the adjustment screw. The "low" actuation point is set by adjusting the
span on the null by turning the span adjustment screw. The span range is .01 - .03" w.c.
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